This invention relates to a telephone office intermediate distributing frame arrangement and more particularly to a switching tool adapted for use on number terminal blocks of intermediate distributing frames.
In a present day telephone switching office, such as a step-by-step office, so-called intermediate distributing frames are utilized to couple subscriber input lines to input leads of live group switches and to output leads of connector switches. The output leads of the connector switches are dedicated or identified with particular subscriber numbers and the input lines of the line group switches are coupled to particular subscriber lines served by the telephone office in question. That is, when a subscriber calls a particular subscriber or telephone number of a telephone office, the calling party is switched by the line group switches to other switching apparatus and ultimately to a particular output line of a connector switch identified with the called number. This output line is coupled to an input line of the line group switches and also to a subscriber line. Of course, the particular called party reached will depend upon which subscriber line is coupled via the intermediate distributing frame to the connector switch output line in question.
Each intermediate distributing frame includes a so-called horizontal side comprised of a plurality of number terminal blocks, and a vertical side comprising a plurality of group terminal blocks. The number terminal blocks and group terminal blocks are typically of similar construction and include groups of connector or terminal posts. There are typically seven terminal posts per group in the number terminal blocks and six terminal posts per group in the group terminal blocks. Three of the terminal posts in each group of the number terminal blocks are coupled to the tip, ring and sleeve of a connector switch output line and three other terminal posts in the group are coupled to intercept apparatus. The seventh terminal post of a group in each number terminal block is for use with apparatus adapted for counting the number of calls, i.e., measured service. Three terminal posts of a group in the group terminal blocks are coupled to the tip, ring and sleeve of an input line of a line group switch and two of the three are also coupled to the tip and ring of a subscriber line. The other three terminal posts of a group are utilized when two-party lines are provided.
As already indicated, when a subscriber is assigned a number, the input line of the line group switches to which the subscriber is connected is coupled by a jumper cable to the output line of the connector switches corresponding to the assigned number. This is accomplished by wire wrapping or soldering one end of a jumper cable to the three terminal posts of the number terminal block to which the connector switch output line is coupled and by wire wrapping or soldering the other end of the jumper cable to the three terminal posts of the group terminal block to which the designated line group switch input line is coupled. The leads from the connector switches are generally coupled to the lower end of the terminal posts of the number terminal blocks and the input leads of the line group switches are similarly coupled to the lower ends of the terminal posts of the group terminal blocks. The intercept apparatus is also coupled to the lower ends of the appropriate terminal posts of the number terminal blocks. The jumper cables are wire wrapped or soldered to the upper ends of the terminal posts.
At the present time, if a subscriber line is to be disconnected, the corresponding jumper cable is removed from the terminal posts of the number terminal block and an intercept tool is placed on the number terminal block to couple the connector switch output line in question to intercept apparatus. The jumper cable is also disconnected from the group terminal block and the jumper cable then repaired or "recycled" for future use. To reconnect or place into service a subscriber line, the intercept tool is removed from the corresponding number terminal block and a new jumper cable is wire wrapped or soldered to the appropriate terminal posts of the number terminal block and a group terminal block. The problems with the present procedure described above for disconnecting and reconnecting subscriber lines is that the jumper cables must be repaired after each disconnection thereof, the number terminal blocks and group terminal blocks must be cleaned from time to time due, for example, to solder droppings, and much time is consumed in installing and removing jumper cables.